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11.
12.
Angela F. Dulhunty Michael R. C. Banyard C. Jill Medveczky 《The Journal of membrane biology》1987,99(2):79-92
Summary Four monoclonal antibodies against the calcium ATPase in sarcoplasmic reticulum (SR) of rabbit fast-twitch skeletal muscle were characterized using SDS-PAGE, Western blots and immunofluorescence. The ultrastructural distribution of the antigens was determined using post-embedding immunolabeling. The antibodies recognized the calcium ATPase in the SR but not in transverse (T-) tubule or plasma membranes. The antibody, D12, had the same binding affinity for the calcium ATPase from fast-twitch (rabbit sternomastoid) and slow-twitch (rabbit soleus) fibers and the affinity fell by 30% after fixation for electron microscopy in both types of muscle fiber. Ultrastructural studies revealed that the density of D12 antibody binding to the terminal cisternae membrane of extensor digitorum longus (edl) and sternomastoid fibers was on average seven times greater than in the slow-twitch soleus and semimembranosus fibers. Since the affinity of the ATPase for the antibody was the same in SR from fast- and slow-twitch muscles, the concentration of calcium ATPase in the terminal cisternae membrane of fast-twitch fibers was seven times greater than in slow-twitch fibers. This conclusion was supported by the fact that the concentration of calcium ATPase in light SR membranes was six times greater in SR from fast-twitch fibers than in SR from slow-twitch fibers. The results provide strong evidence that the different calcium accumulation rates in mammalian fast- and slow-twitch muscles are due to different concentrations of calcium ATPase molecules in the SR membrane. 相似文献
13.
The investigation of crop and soil-crop conditions among Andoke and Witoto cultivators in southeast Colombia is used as a basis for assessing Geertz' (1963) model of swidden cultivation. In this respect, the extent to which maniocdominated swiddens in the study area simulate the structure and composition of the forest climax community is questioned. As Geertz (1963) indicates, an initial nutrient boost for crop cultivation results from the preliminary burning of forest debris, but weed competition, rather than progressive loss of soil fertility, is reported to be the primary cause of abandoning manioc cultivation after 2–3 years. While the Andoke and Witoto crop system remains adaptive at the individual field level, particularly in its constituent species, its fundamental adaptation is considered to be its integration into the broader field and fallow system that juxtaposes crop production with extended periods of forest regeneration. 相似文献
14.
Synopsis The Oreochromis mossambicus population of North Pine Dam, Brisbane, Queensland, Australia was studied over three years, from 1985 to 1988. Basic somatic data were obtained and characteristic values of condition factor, sex ratio, gonosomatic index and the relationships between total and standard lengths, and length and weight, were calculated. Standard length is proportional to total length by the formula SL = –0.321 + 0.799 TL. Weight is related to length by the isometric formula W = aL3. Condition factor values spanned the range 0.0254 to 0.0563, with an average of 0.04078 for males and 0.03877 for females. The sex ratio is 1: 1 until maturity is reached (21 cm SL), at which time the catch rate of the sexes varies due to divergent habitat selection behaviour. Average values of gonosomatic index, considered in relation to maturity classification, are similar to those obtained from other populations, however maximum values are generally much lower, at 0.47 for males and 3.62 for females. These characteristic values are compared, with varying degrees of concordance, with those for populations of this species in other countries. 相似文献
15.
16.
Summary The complete amino acid sequence of the single haemoglobin of the Antarctic fish Aethotaxis mitopteryx DeWitt has been established by automated repetitive Edman degradation on the intact and cleaved (enzymatically and chemically) and chains. A very high sequence identity with other Antarctic fish haemoglobins has been detected. The haemoglobin has a moderate Bohr effect and no Root effect. Organic phosphates and chloride also regulate oxygen binding only to a moderate extent. The lack of Root effect is consistent with the substitution His — Val at the HC3 C-terminal position of the chain. The low overall heat of oxygenation suggests that in this species oxygen transport is an energy-saving process, presumably related to cold adaptation. The comparative analysis of the haemoglobins of Antarctic fishes emphasises some unique features of the oxygen-transport system of A. mitopteryx, which are likely to be related to its also rather unique mode of life.Data presented here were collected during the European Polarstern Study (EPOS) sponsored by the European Science Foundation 相似文献
17.
Michele Solem Angela Helmrich Paul Collodi David Barnes 《Molecular and cellular biochemistry》1991,100(2):141-149
Summary Human S-protein is a serum glycoprotein that binds and inhibits the activated complement complex, mediates coagulation through interaction with antithrombin III and plasminogen activator inhibitor I, and also functions as a cell adhesion protein through interactions with extracellular matrix and cell plasma membranes. A full length cDNA clone for human S-protein was isolated from a lambda gt11 cDNA library of mRNA from the HepG2 hepatocellular carcinoma cell line using mixed oligonucleotide sequences predicted from the amino-terminal amino acid sequence of human S-protein. The cDNA clone in lambda was subcloned into pUC18 for Southern and Northern blot experiments. Hybridization with radiolabeled human S-protein cDNA revealed a single copy gene encoding S-protein in human and mouse genomic DNA. In addition, the S-protein gene was detected in monkey, rat, dog, cow and rabbit genomic DNA. A 1.7 Kb mRNA for S-protein was detected in RNA from human liver and from the PLC/PRF5 human hepatoma cell line. No S-protein mRNA was detected in mRNA from human lung, placenta, or leukocytes or in total RNA from cultured human embryonal rhabdomyosarcoma (RD cell line) or cultured human fibroblasts from embryonic lung (IMR90 cell line) and neonatal foreskin. A 1.6 Kb mRNA for S-protein was detected in mRNA from mouse liver and brain. No S-protein mRNA was detected in mRNA from mouse skeletal muscle, kidney, heart or testis. 相似文献
18.
Cell suspension cultures of the Madagascan Periwinkle Catharanthus roseus (L) G. Don were maintained on Gamborg's B5 medium and their growth monitored by measuring cellular fresh and dry weight, cell number and mitotic activity. Samples of cells of different ages and physiological states were subcultured onto an alkaloid production medium and their rates of growth and alkaloid accumulation measured over a period of 30–45 days. In two experiments the rate of biomass accumulation was directly related to the rate of cellular serpentine accumulation. Possible mechanisms underlying this phenomenon are discussed in relation to the properties of cells comprising the inocula. 相似文献
19.
Sandra N. Hing Carolyn M. Giles Angela H. L. Fielder J. Richard Batchelor 《Immunogenetics》1986,23(3):151-155
Twenty-three individuals from various disease groups and normal controls were identified by immunofixation with anti-C4, C4-dependent lysis, determination of Rg (Rodgers) and Ch (Chido) phenotypes, and immunoblotting with C4-specific mouse monoclonal antibody. We found that one haplotype predominates with the C4B
*
5 allele, HLA-A11, B22(55), Cw3, Bf
*
S, C4A
*
4B
*
5, which also carries the Ch
1,–2, 3 haplotype. The B5 allotype was also found with HLA-1360, HLA-1335 in Caucasoids, and HLA-B18 in non-Caucasoids; these carried the Ch
–1, –2, –3 haplotype. Our results are in accord with an earlier report of two B5 subtypes, B5Rg+ and B5Rg– (Roos et al. 1984). The specificity of the mouse monoclonal antibodies IC4 and 21312 had been previously related to C4A and C4B, respectively, but our results suggest that they relate more closely to Rg and Ch determinants. 相似文献
20.
The brood sac of viviparous Diploptera punctata is a typical insect integumentary gland which secretes a ‘milk’ containing protein and carbohydrate to nourish the developing embryos. During gestation the secretory cells proliferate organelles of protein synthesis and secretion and brood sac wet weight, protein content, synthetic activity and secretory output increase five- to six-fold ; a maximum of 0.4 mg protein was collected in 24 hr from one brood sac in a later stage of gestation. Following parturition, when secretory activity ceases, these parameters fall markedly, and the secretory cells decrease their mass by autophagic regression. Acid phosphatase has been located histochemically in autolysomes and assayed in brood sac homogenates; activity reaches a maximum five days after parturition. 相似文献